Optical diffusion module

ABSTRACT

An optical diffusion structure includes an optical diffusion structure comprising a plurality of convex portions and a plurality of concave portions. Each convex portion is adjacent to a plurality of concave portions and each concave portion is adjacent to a plurality of convex portions. The convex portions, the concave portions and each junction of the convex and concave portions have a curvature different from 0. The optical diffusion structure further includes a diffusion plate having a first surface, wherein the optical diffusion structure is formed on the first surface, and the convex portions are arranged in a two dimensional array along a first direction and a second direction, and the concave portions are arranged in a two dimensional array along a third direction and a fourth direction.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to optical diffusion, and in particular to anoptical diffusion structure with an array of convex portions and concaveportions alternatingly arranged.

2. Description of the Related Art

Light emitting diodes, rather than CCFLs, are applied in backlightmodules due to low cost and simplified structure. To keep the lightsource uniform, an optical diffusion structure is used. For point lightsource or linear light sources, the diffusion structure is usuallydesigned to diffuse light in one or two dimensions.

A conventional backlight module employs a diffusion plate which has ablurred structure, a grained structure or micro-lens array. The blurredstructure causes intensity reduction. The grained structure has smalldiffusion angle and cannot easily control diffusion directions. Themicro-lens array operates at high intensity and is able to control thediffusion direction. The methods of manufacturing micro-lens arraycomprise mechanical methods, thermal fusion methods, or other complexmethods, wherein a laser dragging method is generally used.

A laser dragging method is shown in FIG. 1 a. A laser beam B passesthrough a mask 5 and reaches a substrate 10. When the mask 5 moves in adirection L7, the laser beam etches the substrate 10 to form grooves 12which constitute a micro-lens array. A sharp corner with curvature equalto zero is formed between two grooves 12. The factors for controllinglaser dragging comprise dragging speed, laser power, and number ofrepeated operations, which affect the depth of the grooves 12. Theprofile of the micro-lens array, however, depends on the pattern of themask. Referring to FIG. 1 b, a pattern M3 with large openings and smallopenings is formed on a mask M30. The mask M30 is applied to the laserdragging method to form a plurality of first micro-lenses 202 (concaveportions) and a second micro-lens (convex portions) 204 arrangedalternatingly. The area of the openings determines the etching depth. Anellipse array pattern or circle array pattern can be applied.

FIG. 2 a depicts an optical diffusion structure 200 manufactured by themask M3 in FIG. 1 b along with a diffusion plate 50. FIG. 2 b depictsthe intensity of light passing through the optical diffusion structure200. The stripes in FIG. 2 b represent the area where light iscondensed. Number 30 represents LED array. FIG. 2 c depicts a blurredstructure 210 formed on the back of the optical diffusion structure 200for enhanced light diffusion.

BRIEF SUMMARY OF INVENTION

An optical diffusion structure of the invention comprises a plurality ofconvex portions and a plurality of concave portions. Each convex portionis adjacent to a plurality of concave portions and each concave portionis adjacent to a plurality of convex portions. The convex portions, theconcave portions and each junction of the convex and concave portionshave a curvature other than 0.

An embodiment of the optical diffusion structure of the inventioncomprises a diffusion plate having a first surface, wherein the opticaldiffusion structure is formed on the first surface. The convex portionsare arranged in a two dimensional array along a first direction and asecond direction, and the concave portions are arranged in a twodimensional array along a third direction and a fourth direction.

A detailed description is given in the following embodiments withreference to the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

The invention can be more fully understood by reading the subsequentdetailed description and examples with references made to theaccompanying drawings, wherein:

FIG. 1 a is a schematic view of an optical diffusion structuremanufactured by laser dragging; and

FIG. 1 b depicts a mask used in the laser dragging method and an opticaldiffusion structure manufactured by the mask;

FIG. 2 a depicts an application of the optical diffusion structure ofFIG. 1 b;

FIG. 2 b is an intensity diagram of the optical diffusion structure ofFIG. 2 a;

FIG. 2 c depicts a blurred structure formed on the back of the opticaldiffusion structure;

FIG. 3 is a schematic view of a method of forming an optical diffusionstructure of the invention;

FIG. 4 depicts an optical diffusion structure manufactured by the methodof FIG. 3;

FIG. 5 is an intensity diagram of an embodiment of the optical diffusionstructure of the invention;

FIG. 6 is an intensity diagram of another embodiment of the opticaldiffusion structure of the invention;

FIG. 7 is an intensity diagram of another embodiment of the opticaldiffusion structure of the invention;

FIG. 8 is an intensity diagram of another embodiment of the opticaldiffusion structure of the invention;

FIG. 9 depicts the optical diffusion structure of the invention usedwith a diffusion sheet;

FIG. 10 depicts the optical diffusion structure of the invention usedwith a grained structure;

FIG. 11 depicts the optical diffusion structure of the inventionmanufactured by a polymer with optical diffusion effect;

DETAILED DESCRIPTION OF INVENTION

The invention discloses a two-dimensional optical diffusion structurefor two-dimensional light diffusion. The optical diffusion structure ofthe invention is formed by a laser dragging method.

Referring to FIG. 3, a mask (not shown) is moved along a first directionL1, and laser beams passes through the mask to form a plurality of firstgrooves 520 on a substrate S. The mask is moved along a second directionL2 with laser beams passing therethrough to form a plurality of secondgrooves 540 on the substrate S. The first grooves 520 and the secondgrooves 540 constitute an optical diffusion structure 500 similar tostationary waves.

FIG. 4 depicts an optical diffusion module 600 formed by laser draggingshown in FIG. 3. The optical diffusion structure 600 comprises adiffusion plate 620 and an optical diffusion structure 640 formed on thediffusion plate 620. The optical diffusion structure 640 comprises aplurality of convex portions 660 and a plurality of concave portions680. The convex portions 660 are arranged in a two-dimensional arrayalong the first and second directions. Similarly, the concave portions680 are arranged in a two-dimensional array along the first and seconddirections. The convex portions 660 and the concave portions. 690 arearranged alternatingly to form a pattern similar to stationary waves. Inthis embodiment, each convex portion 660 is adjacent to four concaveportions 680, and each concave portion 680 is also adjacent to fourconvex portions 660. The mask is designed in such a manner thatcurvatures at the convex portions 660, the concave portions 680 and eachjunction of the convex portion 660 and concave portion 680 are differentfrom 0. Along the first direction L1, the distance between two adjacentconvex portions 660 is D1, and the distance between two adjacent concaveportions 680 is D3. Along the second direction L2, the distance betweentwo adjacent convex portions 660 is D2, and the distance between twoadjacent concave portions 680 is D4.

Although D1 is equal to D2, and D3 is equal to D4 in FIG. 4, D1, D2, D3and D4 may different. Other embodiments are described by intensitydiagrams as follows.

FIG. 5 is an intensity diagram for another embodiment of the opticaldiffusion structure of the invention. The stripes in FIG. 5 representbright regions where light is condensed. Distances D1 between any twoadjacent convex portions 660 along the first direction L1 are the same.Distances D3 between any two adjacent concave portions 680 along thefirst direction L1 are the same. Distances D2 between any two adjacentconvex portions 660 along the second direction L2 are the same.Distances D4 between any two adjacent concave portions 680 along thesecond direction L2 are the same.

FIG. 6 is an intensity diagram for another embodiment of the opticaldiffusion structure of the invention. Distances D1 between any twoadjacent convex portions 660 along the first direction L1 are the same.Distances D3 between any two adjacent concave portions 680 along thefirst direction L1 are the same. Distances D2 between any two adjacentconvex portions 660 along the second direction L2 are different.Distances D4 between any two adjacent concave portions 680 along thesecond direction L2 are different. D2 and D4 increase gradually from acenter of the optical diffusion structure 640 to lateral sides thereof.

FIG. 7 is an intensity diagram for another embodiment of the opticaldiffusion structure of the invention. Distances D1 between any twoadjacent convex portions 660 along the first direction L1 are the same.Distances D3 between any two adjacent concave portions 680 along thefirst direction L1 are the same. Distances D2 between any two adjacentconvex portions 660 along the second direction L2 are different.Distances D4 between any two adjacent concave portions 680 along thesecond direction L2 are different. D2 and D4 decrease gradually from acenter to lateral sides of the optical diffusion structure 640.

FIG. 8 is an intensity diagram for another embodiment of the opticaldiffusion structure of the invention. Distances D1 between any twoadjacent convex portions 660 along the first direction L1 are different.Distances D3 between any two adjacent concave portions 680 along thefirst direction L1 are different. D1 and D3 increase gradually from acenter to lateral sides of the optical diffusion structure 640.Distances D2 between any two adjacent convex portions 660 along thesecond direction L2 are different. Distances D4 between any two adjacentconcave portions 680 along the second direction L2 are different. D2 andD4 increase gradually from a center to lateral sides of the opticaldiffusion structure 640.

The embodiments above are examples for description, but the invention isnot limited thereto. For example, distances D1 between two adjacentconvex portions 660 are different along the first direction L1, butDistances D3 between any two adjacent concave portions 680 along thefirst direction L1 are the same.

In addition, although the first direction L1 and the second direction L2in the described embodiments are perpendicular, the first direction L1and the second direction L2 can also be other than perpendicular.

The diffusion plate 620 can be combined with a typical diffusion plate50 to constitute an optical diffusion module 700 shown in FIG. 9. Number30 is a LED array. In FIG. 10, an optical diffusion module 800 comprisesa grained structure or a blurred structure formed on the bottom (secondsurface) 622 of the diffusion plate 620 (the optical diffusion structure600 is formed on the first surface 621) to enhance light diffusion. InFIG. 11, an optical diffusion module 900 comprises the diffusion plate620 of a polymer with light diffusion characteristics.

While the invention has been described by way of example and in terms ofpreferred embodiment, it is to be understood that the invention is notlimited thereto. To the contrary, it is intended to cover variousmodifications and similar arrangements (as would be apparent to thoseskilled in the art). Therefore, the scope of the appended claims shouldbe accorded the broadest interpretation so as to encompass all suchmodifications and similar arrangements.

1. An optical diffusion module, comprising: an optical diffusionstructure comprising a plurality of convex portions and a plurality ofconcave portions, wherein each convex portion is adjacent to a pluralityof concave portions and each concave portion is adjacent to a pluralityof convex portions, and the convex portions, the concave portions andeach junction of the convex and concave portions have a curvaturedifferent from 0; and a diffusion plate having a first surface, whereinthe optical diffusion structure is formed on the first surface, and theconvex portions are arranged in a two dimensional array along a firstdirection and a second direction, and the concave portions are arrangedin a two dimensional array along a third direction and a fourthdirection.
 2. The optical diffusion module as claimed in claim 1,wherein distances from one convex portion to other convex portions,which are adjacent to the one convex portion, are the same along thefirst direction.
 3. The optical diffusion module as claimed in claim 2,wherein distances from one convex portion to other convex portions,which are adjacent to the one convex portion, are the same along thesecond direction.
 4. The optical diffusion module as claimed in claim 3,wherein distances from one concave portion to other concave portions,which are adjacent to the one concave portion, are the same along thefirst direction.
 5. The optical diffusion module as claimed in claim 4,wherein distances from one concave portion to other concave portions,which are adjacent to the one concave portion, are the same along thesecond direction.
 6. The optical diffusion module as claimed in claim 1,wherein distances from one convex portion to other convex portions,which are adjacent to the one convex portion, are different along thesecond direction.
 7. The optical diffusion module as claimed in claim 6,wherein the distance from one convex portion to another convex portion,which is adjacent to the one convex portion, decreases from a center tolateral sides of the optical diffusion structure along the seconddirection.
 8. The optical diffusion module as claimed in claim 6,wherein the distance from one convex portion to another convex portion,which is adjacent to the one convex portion, increases from a center tolateral sides of the optical diffusion structure along the seconddirection.
 9. The optical diffusion module as claimed in claim 6,wherein distances from one concave portion to other concave portions,which are adjacent to the one concave portion, are the same along thefirst direction.
 10. The optical diffusion module as claimed in claim 9,wherein distances from one concave portion to other concave portions,which are adjacent to the one concave portion, are different along thesecond direction.
 11. The optical diffusion module as claimed in claim10, wherein the distance from one concave portion to another concaveportion, which is adjacent to the one concave portion, decreases from acenter to lateral sides of the optical diffusion structure along thesecond direction.
 12. The optical diffusion module as claimed in claim10, wherein the distance from one concave portion to another concaveportion, which is adjacent to the one concave portion, increases from acenter to lateral sides of the optical diffusion structure along thesecond direction.
 13. The optical diffusion module as claimed in claim1, wherein distances from one convex portion to other convex portions,which are adjacent to the one convex portion, are different along thefirst direction.
 14. The optical diffusion module as claimed in claim13, wherein distances from one convex portion to other convex portions,which are adjacent to the one convex portion, are different along thesecond direction.
 15. The optical diffusion module as claimed in claim14, wherein the distance from one convex portion to another convexportion, which is adjacent to the one convex portion, decreases from acenter to lateral sides of the optical diffusion structure along thefirst direction.
 16. The optical diffusion module as claimed in claim15, wherein the distance from one convex portion to another convexportion, which is adjacent to the one convex portion, decreases from acenter to lateral sides of the optical diffusion structure along thesecond direction.
 17. The optical diffusion module as claimed in claim15, wherein the distance from one convex portion to another convexportion, which is adjacent to the one convex portion, increases from acenter to lateral sides of the optical diffusion structure along thesecond direction.
 18. The optical diffusion module as claimed in claim14, wherein the distance from one convex portion to another convexportion, which is adjacent to the one convex portion, increases from acenter to lateral sides of the optical diffusion structure along thefirst direction.
 19. The optical diffusion module as claimed in claim18, wherein the distance from one convex portion to another convexportion, which is adjacent to the one convex portion, increases from acenter to lateral sides of the optical diffusion structure along thesecond direction.
 20. The optical diffusion module as claimed in claim13, wherein distances from one concave portion to other concaveportions, which are adjacent to the one concave portion, are differentalong the first direction.
 21. The optical diffusion module as claimedin claim 20, wherein distances from one concave portion to other concaveportions, which are adjacent to the one concave portion, are differentalong the second direction.
 22. The optical diffusion module as claimedin claim 1 further comprising a diffusion layer, wherein light from alight source passes through the diffusion layer and the diffusion platesequentially.
 23. The optical diffusion module as claimed in claim 1,wherein the diffusion plate further has a second surface on which agrained structure is formed, and light from a light source passesthrough the second surface and the first surface sequentially.
 24. Theoptical diffusion module as claimed in claim 1, wherein the diffusionplate further has a second surface on which a blurred structure isformed, and light from a light source passes through the second surfaceand the first surface sequentially.
 25. The optical diffusion module asclaimed in claim 1, wherein the diffusion plate is made of polymer withoptical diffusion effect.
 26. An optical diffusion module, comprising:an optical diffusion structure comprising a plurality of convex portionsand a plurality of concave portions, wherein each convex portion isadjacent to a plurality of concave portions and each concave portion isadjacent to a plurality of convex portions, and the convex portions, theconcave portions and each junction of the convex and concave portionshave a curvature different from 0; and a diffusion sheet on which thediffusion structure is formed, wherein the convex and concave portionsof the diffusion structure extend along a first direction and arearranged alternatingly along a second direction, and each convex portionis curved and has a first curved surface having a first width along thesecond direction, which is varied along the second direction, and eachconcave portion is curved and has a second curved surface having asecond width along the second direction, which is varied along thesecond direction.
 27. The optical diffusion module as claimed in claim26, wherein the first width decreases from a center to lateral sides ofthe first diffusion structure.
 28. The optical diffusion module asclaimed in claim 27, wherein the second width decreases from a center tolateral sides of the first diffusion structure.
 29. The opticaldiffusion module as claimed in claim 26, wherein the first widthincreases from a center to lateral sides of the first diffusionstructure.
 30. The optical diffusion module as claimed in claim 29,wherein the second width increases from a center to lateral sides of thefirst diffusion structure.
 31. The optical diffusion module as claimedin claim 29 further comprising a diffusion layer, wherein the light fromthe light source passes through the diffusion layer and the diffusionstructure sequentially.
 32. A method of forming an optical diffusionstructure, comprising: providing a substrate; providing a first maskhaving a plurality of first holes arranged in a array; providing asecond mask having a plurality of second holes arranged in an array;providing an energy beam; placing the first mask between the energy beamand the substrate; moving the first mask or the substrate along a firstdirection; placing the second mask between the energy beam and thesubstrate; moving the second mask or the substrate along a seconddirection to form a two dimensional array of convex portions and concaveportions on the substrate, wherein each convex portion is adjacent to aplurality of concave portions and each concave portion is adjacent to aplurality of convex portions.
 33. The method as claimed in claim 32,wherein the first direction is perpendicular to the second direction.34. The method as claimed in claim 32, wherein distances between onefirst hole to other first holes, which are adjacent to the one firsthole, are the same.
 35. The method as claimed in claim 34, whereindistances between one second hole to other second holes, which areadjacent to the one second hole, are the same.
 36. The method as claimedin claim 34, wherein distances between one second hole to other secondholes, which are adjacent to the one second hole, are different.
 37. Themethod as claimed in claim 32, wherein distances between one first holeto other first holes, which are adjacent to the one first hole, aredifferent, and distances between one second hole to other second holes,which are adjacent to the one second hole, are different.
 38. A methodof forming an optical diffusion structure, comprising: providing asubstrate; providing a mask having a plurality of holes arranged in anarray; providing an energy beam; placing the mask between the energybeam and the substrate; moving the mask or the substrate along a firstdirection; and moving the mask or the substrate along a second directionto form a two dimensional array of convex portions and concave portionson the substrate, wherein each convex portion is adjacent to a pluralityof concave portions and each concave portion is adjacent to a pluralityof convex portions.
 39. The method as claimed in claim 38, wherein thefirst direction is perpendicular to the second direction.